Chip sized package

Abstract

An improved wafer based packaging arrangement for integrated circuits is disclosed. In one aspect of the invention, external contacts are formed for the packaged integrated circuits by contact studs formed from bonding wires. One end of each contact studs is ball bonded to an associated wafer bond pad. An elongated portion of each wire (contact stud) extends outward the wafer surface and terminates at a second end that forms an external contact. Filling material surrounds a significant portion of the contact studs to hold the studs in place but leaves at least a portion of the second ends exposed to form external contacts. In some embodiments, the external contacts are substantially coplanar with the surface of the filling material, while in others, a protrusion beyond the filling material surface is left to form a contact bump. The wafers are eventually diced to form discrete packaged integrated circuits having external contacts formed by the contact studs.

We claim: 
     
       1. A packaged integrated circuit comprising: an integrated circuit package component having a multiplicity of bond pads arranged on a first surface thereof;   a multiplicity of bonding wire contacts having substantially uniform heights, each bonding wire having a first end that is ball bonded to an associated bond pad and an elongated portion that extends substantially perpendicularly to the first surface of the integrated circuit package component and terminates at a second end that forms an external contact, the elongated portion being formed from substantially unmelted bonding wire and having a height of greater than approximately 20 mils;   a filling material that surrounds a significant portion of the bonding wires to hold the bonding wires in place, but leaves at least a portion of the second ends exposed to form external contacts.   
     
     
       2. A packaged integrated circuit as recited in claim 1 wherein the integrated circuit package component is a die and the external contacts are substantially coplanar with a surface of the filling material. 
     
     
       3. A packaged integrated circuit as recited in claim 1 wherein the integrated circuit package component is a die and the external contacts are bumps that rise above a surface of the filling material. 
     
     
       4. A packaged integrated circuit as recited in claim 1 wherein the filling material is an epoxy type material that covers only the first surface of the integrated circuit package component. 
     
     
       5. A packaged integrated circuit as recited in claim 1 further comprising contact balls formed at the second ends of the respective contact studs to form the external contacts, the contact balls having a diameter greater than that of the elongated portion of their associated bonding wires and being integrally formed with their associated bonding wires during flame off of the second ends of the bonding wires. 
     
     
       6. A packaged integrated circuit comprising: an integrated circuit package component having a multiplicity of bond pads arranged on a first surface thereof;   a multiplicity of bonding wire contacts, each bonding wire having a first end that is ball bonded to an associated bond pad, an elongated portion, and a contact ball at a second end that forms an external contact, the contact ball having a diameter greater than that of the elongated portion of the associated bonding wire, and being integrally formed with the bonding wire during flame off of the second end of the bonding wire, the elongated portion being formed from substantially unmelted bonding wire; and   a filling material that surrounds a significant portion of the bonding wires to hold the bonding wires in place, but leaves at least a portion of the second ends exposed to form external contacts.   
     
     
       7. A packaged integrated circuit as recited in claim 6 wherein the integrated circuit package component is a die and the external contacts are substantially coplanar with a surface of the filling material. 
     
     
       8. A packaged integrated circuit as recited in claim 6 wherein the integrated circuit package component is a die and the contact balls form bumps that rise above a surface of the filling material. 
     
     
       9. A packaged integrated circuit as recited in claim 6 wherein the filling material is an epoxy type material that covers only the first surface of the integrated circuit package component. 
     
     
       10. A semiconductor wafer comprising: a plurality of dice, each integrated circuit package component having a multiplicity of bond pads arranged on a first surface of the wafer;   a multiplicity of bonding wire contacts, each bonding wire having a first end that is ball bonded to an associated bond pad and an elongated portion that extends substantially perpendicularly to the first surface of the wafer and a contact ball at a second end that forms an external contact, the contact ball having a diameter greater than that of the elongated portion of the associated bonding wire and being integrally formed with the bonding wire during flame off of the second end of the bonding wire, the cross-sectional areas along a continuous length of said elongated portion being substantially uniform; and   a filling material that surrounds a significant portion of the bonding wires to hold the bonding wires in place but leaves at least a portion of the second ends exposed to form external contacts.   
     
     
       11. A semiconductor wafer as recited in claim 10 wherein the external contacts are substantially coplanar with a surface of the filling material. 
     
     
       12. A packaged integrated circuit as recited in claim 6 wherein the elongated portion has a height in the range of approximately 20 to 50 mils. 
     
     
       13. A packaged integrated circuit as recited in claim 1 wherein the elongated portion has a height between approximately 20 and 30 mils. 
     
     
       14. A packaged integrated circuit as recited in claim 6 wherein the elongated portion has a diameter of greater than 1.6 mil. 
     
     
       15. A packaged integrated circuit comprising: an integrated circuit package component having a multiplicity of bond pads arranged on a first surface thereof;   a multiplicity of bonding wire contacts having substantially uniform heights, each bonding wire having a first end that is ball bonded to an associated bond pad and an elongated portion that extends substantially perpendicularly to the first surface of the integrated circuit package component and terminates at a second end that forms an external contact, the elongated portion being formed from substantially unmelted bonding wire and having a diameter greater than 1.6 mils; and   a filling material that surrounds a significant portion of the bonding wires to hold the bonding wires in place, but leaves at least a portion of the second ends exposed to form external contacts.